The goal of this project is the prevention or control of trachoma, the world's most important cause of blindness, and of related infections with Chlamydia trachomatis. The goal is sought through better understanding of the pathogenesis, immunology and epidemiology of trachoma and the related diseases and through studies of the microorganisms. The related diseases that will be investigated are conjunctivitis of the newborn, and other sequelae of birth canal infections with C. trachomatis. Field investigations will be carried out in Taiwan. Isolation of the organism in HeLa 229 cell culture and use of the micro immunofluorescence test which measures type specific antibody in serum and local secretions will assist in the studies of human disease. Efforts will be made to further simplify this serologic technique and to better understand the interrelationship of the 15 immunotypes of C. trachomatis. Attempts will be made to identify and isolate subspecies and specific antigens of C. trachomatis.